The invention relates to a medical apparatus, comprising a stand with an approximately L-shaped arm which comprises a first portion having a free end which is connected, via a bearing, to a boundary surface of an examination space in such a manner that it can be rotated from a neutral position into opposite directions through an angle of .alpha. radians in a plane of rotation which is parallel to said boundary surface, and also comprises a second portion which extends approximately perpendicularly to the first portion and to a free end of which there is attached at least one medical apparatus, a bundle of cables extending from a space at the side of the boundary surface which is remote from the examination space to parts of the apparatus.
An apparatus of this kind is known, for example from EP-A-0 506 172 (PHN 13.642). The boundary surface may be, for example the floor or the ceiling of the examination space. In the known apparatus an X-ray source and an X-ray detector, for example an X-ray image intensifier tube, are attached to the free end of the second portion via a support. The support may be, for example a C-arc which is rotatably connected to the free end of the second portion of the arm. The X-ray source and the X-ray detector are attached to oppositely situated ends of the C-arc. The bundle of cables comprises, for example power supply cables for powering the apparatus, tubes for the supply of cooling liquid and signal cables for transmitting instructions to the apparatus and for transferring measurement signals from the apparatus to processing equipment installed elsewhere. The cables preferably extend in a cable trough provided behind the boundary surface. In the known apparatus the cables extend freely, or via ornamental tubes, from the boundary surface to the relevant parts of the apparatus. The cables and ornamental tubes extending freely through the examination space, however, are not only unhygienic and ugly but also interfere with personnel attending the apparatus. The latter is the case notably when said boundary surface is the floor of the examination space. The cables are then spread across the floor so that an operator could easily trip over the cables.
It is an object of the invention to provide an apparatus of the kind set forth in which the cables can extend almost invisibly from the boundary surface to the relevant parts of the apparatus. To achieve this, the apparatus in accordance with the invention is characterized in that the bundle of cables is shaped as an approximately flat ribbon having a largest thickness t equal to the thickness of the thickest cable of the bundle and a width w equal to the sum of the thicknesses of the cables, and extends to the free end of the second portion via an opening in the boundary surface at the area of the bearing and a cavity formed in the arm and extending over the entire length of the arm, said cavity having an approximately rectangular cross-section of a width which at least equals w and a height which at least equals t, the width direction of the cavity in the first portion of the arm extending substantially parallel to the boundary surface, the cables of the bundle being secured in a first cable holder which is situated at the side of the bearing remote from the second portion of the arm and defines the positions of the cables relative to one another. and that at the area of the transition between the first and the second portion of the arm there is provided a protrusion so that the height of the cavity in the second portion of the arm locally equals at least t+.alpha.w.
The entire bundle of cables now extends through the tubular cavity in the arm. Because the bundle is shaped as a flat ribbon, the transverse dimensions of the arm need not be larger, or only hardly larger, than required already for constructional reasons. During rotation the ribbon of cables is forced to make a bend, so that the cables situated at the outer side are pulled and the cables situated further inwards are pushed back. The protrusion serves to accommodate the cable slack thus occurring, so that the cable bundle as a whole retains the shape of a flat ribbon and the cables are not damaged.
It is to be noted that NL-A-81 01 448 discloses a medical apparatus with a pivot arm in which cables extend. In this apparatus, however, the pivot arm is not L-shaped and, moreover, the transverse dimension of the pivot arm is comparatively large because the am must be provided with cavities having a substantially square cross-section for the cables.
A preferred embodiment of the apparatus in accordance with the invention is characterized in that near the protrusion in the second portion of the arm, there is provided a second cable holder which defines the positions of the cables relative to one another. The movement of the cables relative to one another, caused by rotation of the arm, is thus limited to the part of the bundle of cables extending between the two cable holders.
A further preferred embodiment of the apparatus in accordance with the invention is characterized in that the bundle of cables extends through an opening formed in the ring-shaped bearing. As a result of this step, the height of the arm at the area of the bearing may be minimum, thus minimizing the volume occupied by the apparatus.